function scont (urls) {
	$.getJSON(urls,{},function(data) {					
				for (var i=0;i<data.length;i++) {					
					$(".dnav_txt").html(data[0].mediaList["0"].nav_title);
					var datas=data[i];						
					var $pictxt=$("#pro").clone(true);
					$pictxt.find("img").attr("src2",datas.mediaList["0"].coverPic).addClass("newimg");
					$pictxt.find(".bookname").text("书名："+datas.mediaList["0"].title);
					$pictxt.find(".bookintrod").text("简介："+datas.mediaList["0"].descs);
					$pictxt.find(".bookauthor").text("作者："+datas.mediaList["0"].authorPenname);
					$pictxt.show();
					$(".class_cnt").append($pictxt);
					
					
				}
	});
	
	     window.onscroll = function(){  
               var st = document.body.scrollTop||document.documentElement.scrollTop;
                var ch = document.body.clientHeight||document.documentElement.clientHeight;
                 
                
                $(".newimg").each(
                    function(){                      
                       var imgtop = $(this).offset().top;
                        if(imgtop>st&&imgtop<st+ch-60){                        	
                            $(this)[0].className = "oldimg";
                            $(this).attr("src",$(this).attr("src2"));
                        }
                    }
                );      
             }   
 

	
	
}